tread: [OE] Tread comes from a prehistoric Germanic *trethan, which also produced German treten, Dutch treden, Swedish träda, and Danish træde. It does not appear to have any relations outside Germanic, however. Trade comes from the same base, and it is thought that trot [13] may do so too, although its immediate source was Old French troter.=> trade, trot[tread etymology, tread origin, 英语词源]